In this article, we propose a double-sided electromagnetic bandgap (DS-EBG) structure for glass interposers (GIs) with low substrate loss to suppress power/ground noise. For the first time, we ...validated wideband power/ground noise suppression in the GI using the proposed DS-EBG structure based on dispersion analysis and experimental verification. We experimentally verified that the proposed DS-EBG structure achieved the power/ground noise suppression (below −40 dB) between 2.5 and 8.9 GHz in the GI. Derived stopband edges, <inline-formula> <tex-math notation="LaTeX">f_{L} </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">f_{U} </tex-math></inline-formula> based on the dispersion analysis, and 3-D electromagnetic (EM) simulation showed a good correlation with measurements. The effectiveness of the proposed DS-EBG structure on the power/ground noise suppression is verified by analyzing noise propagation in the power distribution network and coupling to the GI channel. Using the 3-D EM simulation, we verified that the proposed DS-EBG structure suppressed the power/ground noise coupling and improved the eye diagram of the GI channel. Finally, we propose a design methodology to broaden the isolation bandgap or miniaturize the dimensions based on the dispersion analysis.
Flex-on-board (FOB) interconnection plays an important role in display applications. Due to the thinness of the interconnect, the contact resistance of anisotropic conductive film (ACF) joints is ...very small; however, the transmission property of ACF joints are still unknown. In this study, we designed a novel coplanar waveguide structure to characterize the transmission properties of ACF joints in FOB interconnections. Specifically, we compared the differences between the Au/Ni coated polymer ball joint and low melting point Sn58Bi solder ball joint in terms of their high frequency performance. Both were bonded under the same conditions of 200 °C for 10 s at 2 MPa. A high frequency test was then carried out in the range of 300 MHz to 20 GHz. The results showed that 14 GHz was the resonant frequency of FOB package that contained the Au/Ni coated polymer ball joints, while 1 GHz increased by using Sn58Bi solder joints in FOB package. To our knowledge, there is the first study to determine the high frequency performance of flex-on-board interconnections using ACFs joints and the coplanar waveguide method.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this paper, we propose glass-interposer (GI) electromagnetic bandgap (EBG) structure with defected ground plane (DGP) for efficient and broadband suppression of power/ground noise coupling. We ...designed, fabricated, measured, and analyzed a GI-EBG structure with DGP for the first time. The proposed GI-EBG structure with DGP is thoroughly analyzed using the dispersion characteristics and estimated stopband edges, f L and f U . We experimentally verified that the proposed GI-EBG structure with DGP achieved power/ground noise isolation bandgap (below -30 dB) between f L of 5.7 GHz and f U of 11 GHz. Estimation of f L and f U using dispersion analysis, full 3-D electromagnetic (EM) simulation results, and measurement results achieved good correlation. Effectiveness of the proposed GI-EBG structure with DGP on suppression of the power/ground noise coupling to high-speed through glass via (TGV) channel is verified with 3-D EM simulation. As a result, the proposed EBG structure successfully and efficiently suppressed the power/ground noise coupling and improved the eye diagram of the TGV channel. Lastly, we embedded thin alumina film in the proposed EBG structure and achieved even broader power/ground noise suppression between 2.1 and 14.7 GHz.
In this paper, we design and analyze the receiver channel of a glass interposer for a dual band Wi-Fi front end module (FEM). In RF systems, a RF sensitivity is the most important specification for a ...system performance and reliability. To guarantee a target RF sensitivity of the RF system, it is important to maintain a 50 Ohm impedance matching for RF channels. The 50 Ohm impedance matching of various transmission line structures is completely conducted for each layer of the glass interposer in a low band (2.4GHz - 2.5GHz) and high band (4.9GHz - 5.85GHz) respectively. Channel types for each layer are determined considering design rules and constraints. Moreover, we locate ground TGVs near signal TGVs as close as possible to suppress a ground-ground cavity resonance effect in the low band and high band. In order to test a suppression of the ground-ground cavity resonance, simulations that compare pitches between a ground TGV and signal TGV are conducted. Design considerations of receiver channels were analyzed and characterized by simulation results of channel insertion losses.
In this article, we first propose a deep reinforcement learning (RL)-based optimal decoupling capacitor (decap) design method for silicon interposer-based 2.5-D/3-D integrated circuits (ICs). The ...proposed method provides an optimal decap design that satisfies target impedance with a minimum area. Using deep RL algorithms based on reward feedback mechanisms, an optimal decap design guideline can be derived. For verification, the proposed method was applied to test power distribution networks (PDNs) and self-PDN impedance was compared with full search simulation results. We successfully verified by the full search simulation that the proposed method provides one of the solution sets. Conventional approaches are based on complex analytical models from power integrity (PI) domain expertise. However, the proposed method requires only specifications of the PDN structure and decap, along with a simple reward model, achieving fast and accurate data-driven results. Computing time of the proposed method was a few minutes, significantly reduced than that of the full search simulation, which took more than a month. Furthermore, the proposed deep RL method covered up to <inline-formula> <tex-math notation="LaTeX">10^{17} </tex-math></inline-formula>-<inline-formula> <tex-math notation="LaTeX">10^{18} </tex-math></inline-formula> cases, an approximately <inline-formula> <tex-math notation="LaTeX">10^{12} </tex-math></inline-formula>-<inline-formula> <tex-math notation="LaTeX">10^{13} </tex-math></inline-formula> order increase compared to the previous RL-based methods that did not utilize deep-learning techniques.
In this article, we first measured through glass via (TGV) noise coupling and the effectiveness of shielding structures in a glass interposer. To analyze the noise coupling between signal TGVs, an ...open-ended structure is adopted. Glass interposer test vehicles were fabricated to verify the noise coupling between signal TGVs. With these test vehicles, noise transfer functions between signal TGVs were measured. Based on these measurement results and the equivalent circuit model, the noise coupling between signal TGVs was analyzed. To suppress this TGV noise coupling, shielding structures for the TGV noise coupling were proposed and verified. The proposed shielding structures include the variation of signal TGV pitches and the number of grounded shield TGVs, ground pads, and guard rings, respectively. The effectiveness of the proposed shielding structures was verified up to 20 GHz in frequency-domain measurements. Using the proposed shielding structures, the noise transfer function decreased by 9.4 dB at 5 GHz. Also, the effectiveness of the proposed guard ring structure was verified by a time-domain coupling noise simulation with clock signals at frequencies of 1 GHz. The proposed guard ring successfully suppressed the clock noise coupling between signal TGVs by 60.5% and 69.2% when a signal TGV pitchis 300 and 900 <inline-formula><tex-math notation="LaTeX">\mu {\text{m}}</tex-math></inline-formula>, respectively.
This paper proposes eye diagram estimation methods for linear feedback shift register (LFSR)-based bit streams in pseudorandom binary sequence (PRBS) test and scrambling. The PRBS test uses the LFSR ...as a random data source; scrambling suppresses the radiated EMI by exclusive-OR (XOR) between the data and the LFSR. Both cases include the LFSR as the last block, thus, the LFSR dominantly determines the eye diagram. This paper introduced the deterministic and statistical eye diagram for the PRBS test and scrambling, respectively. The deterministic eye diagram was verified by comparing to the measurement; the statistical eye diagram was verified by comparing to the transient simulation. We also compared the voltage bathtub curves for the scrambling. The measurement and proposed method were correlated up to the BER of 10 -10 .
In this paper, we, for the first time, designed and analyzed differential high-speed serial links of the silicon interposer including differential through-silicon-via (TSV) channels for a ...high-bandwidth memory (HBM) graphic module. The meshed ground plane and various parameters were considered in designing the silicon interposer. In addition, superior designs were proposed to improve signal integrity (SI) for the differential channels in the redistribution layer, TSVs, and the meshed ground. SI of the silicon interposer was successfully analyzed, and the corresponding results were verified based on a full 3-D electromagnetic solver and circuit simulations. A number of RLGC parameters were extracted and calculated, then adopted to verify the simulation results. The simulation results for the differential characteristic impedance and insertion loss were compared with those of the equivalent circuit. A mixed-mode conversion matrix was utilized to analyze differential-mode transmission. Moreover, a model for differential TSV channels was proposed to precisely analyze the electrical characteristics. The eye-diagram simulation was conducted to evaluate SI of the proposed designs in terms of an eye-opening voltage and timing jitter. The eye-opening voltage of the proposed design was 0.594 V, which is 45.69% of a peak-to-peak voltage of the assumed peripheral component interconnect (PCI)-express 4.0 interfaces. It is expected that the analysis and design methodologies of differential high-speed serial links for a silicon interposer could be widely adopted in the semiconductor industry.
In this article, we propose an embedded cooling structure with thermal transmission line (ECS-TTL) to improve thermal integrity (TI) and signal integrity (SI) of a high-bandwidth memory (HBM) module. ...The proposed hierarchical cooling scheme, ECS-TTL, consists of ECS for lowering thermal resistance and TTL for smoothing thermal distribution. The ECS cools the module's integrated circuits by circulating fluid inside the computing module components. The TTL is a novel interconnection that focuses on transferring internal heat in a horizontal direction to achieve a uniform thermal distribution. The low and uniform thermal distribution achieved by the ECS-TTL can improve the temperature-dependent SI of an HBM module. We designed ECS-TTL by considering the structural reliability and SI of the HBM module based on its physical dimensions. We conducted TI verification of the HBM module by using a 3-D computational fluid dynamics solver; we evaluated the maximum temperature and the temperature uniformity of the HBM module with the proposed ECS-TTL and other cooling structures. Based on the TI evaluation, we conducted SI verification of the HBM by using a 3-D electromagnetic solver considering the operating thermal distribution; we evaluated the eye diagram and skew of the silicon interposer, through silicon via channels and a 3-D clock distribution network in the HBM. The evaluation verified that the proposed ECS-TTL can achieve a low and uniform thermal distribution while improving the eye diagram and skew of the HBM module compared to the conventional cooling structure.
This paper, for the first time, proposed a novel eye-diagram estimation method for pulse amplitude modulation with N-level (PAM-N) signaling. For verification, a through-silicon via (TSV) channel was ...fabricated. Because the input of the proposed method is an insertion loss, the loss of the fabricated TSV channel was measured up to 110 GHz. The estimated eye diagrams and measured eye diagrams were compared for the same TSV channel. The proposed method and measurements have nearly the same eye-height and eye-width values at data rates of 2, 4, and 8 Gb/s. Therefore, the proposed method successfully provides PAM-N's eye diagram with the insertion loss. Furthermore, bathtub curves were compared for the proposed method and measurements. The proposed method provides a bathtub curve up to 10-12, but in contrast, the measurements only provide a bathtub curve up to 10-5 due to a limited number of samples. Both of the bathtub curves are nearly the same up to 10-5 in amplitude. In conclusion, the eye-diagram estimation method for PAM-N signaling is successfully proposed and verified.
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